Underwater breathing device



April 10, 1962 .w F. MITCHELL 3,028,859

UNDERWATER BREATHING DEVICE Filed Sept. 19, 1955 3 sheets-sheet 1 QJ IV'2' INVENToR.

, lQQNALLAm-I F. MITCHELL nJ/eha' Cri/M ATTORNEYS April 10, 19.62 w. F.MITCHELL 3,028,859

UNDERWATER BREATHING DEVICE Filed Sept. 19, 1955 5 Sheets-Sheet 2ATTORNEYS April 10, 1952 W. F. MITCHELL 3,028,859

UNDERWATEE BREATHING DEVICE Filed Sept. 19, 1955 3 Sheets-Sheet 3 FIG. 6

INVENTOR.

3o WALLACE F. MITCHELL ATTORNEYS Unite States Patent 3,028,859UNDERWATER BREATHING DEVICE Wallace F. Mitchell, Arlington Heights,Ill., assigner to Dacor Corporation, a corporation of Illinois FiledSept. 19, 1955, Ser. No. 535,067 9 Claims. (Cl. 12S-142) This inventionrelates to underwater breathing devices and has to do more particularlywith an underwater breathing device of the self-contained type.

Self-contained underwater breathing devices as heretofore constructedhave usually included a tank of compressed air, an air intake hose lineleading from the tank to a mouthpiece adapted to be held in the mouth ofthe user and an exhaust air hose line leading from the mouthpiece to aone-way discharge or exhaust valve. Connected to the intake line is apressure regulator adapted to reduce the pressure of the compressed airto that of the surrounding water and to avoid the loss of air. In suchdevices the pressure regulator includes a regulator chamber defined inpart by a flexible diaphragm which is exposed at one face to the waterand consequently is subjected to the pressure of the water, thediaphragm being arranged to cause the opening of a demand valve in theregulator leading to the intake hoseline Whenever the pressure in theintake line is a predetermined amount less than the water pressure, suchas when the user inhales. It was found that such devices were subject toloss of air through the exhaust valve due to the spontaneous opening ofthe latter whenever the pressure exerted by the water on the diaphragmexceeded that exerted by the water on the exhaust valve by an amountequal to that suiicient to cause the diaphragm to open the demand valve.In order to prevent such spontaneous escape of air it has been proposedto locate the exhaust valve at a distance from the center pressure ofthe diaphragm less than the height of a column of water representing thepressure necessary for operation of the demand valve. This not onlyplaces serious and undesirable limitations on the design of the devicebut also places a limitation on the pressure necessary to operate thedemand valve.

Another prior art proposal has been to locate the exhaust Valve in achamber having a restricted outlet opening whereby when the exhaustvalve is in a position above the level of the diaphragm, the chamberopening is downwardly and lower than the diaphragm, and air therefore istrapped in the chamber to prevent water Vfrom acting directly on theexhaust valve, with the result that the pressure on the exhaust valve isequal to that of the water at the chamber opening which is greater thanthe water pressure on the diaphragm. This proposal also imposes seriouslimitations on the design of the device.

The prior art devices also are subject to other disadvantages. The useof a single valve-operating diaphragm renders the device vulnerable uponrupture or leakage of the diaphragm, upon which occurrence the demandvalve can no longer be operated by the user inhaling and the air supplytherefore is eifectively cut off. Also, the single diaphragm is exposedto the water on one face and consequently is subjected to the inertia ofthe water and thus the breathing action is made more difficult and lessuniform than would be the case if the diaphragm were operated with airon both faces.

An object of my invention is to provide a new and improved,self-contained, underwater breathing device.

Another object is to provide a self-contained underwater breathingdevice which is not susceptible to spontaneous loss of air therefromregardless of the position of the device in the water. I

A further object is to provide a self-contained underwater breathingdevice wherein the exhaust valve may be disposed in any locationrelatively to the diaphragm ICC which controls the operation of thelair-demand valve without causing spontaneous loss of air therethrough.

A further object of my invention is to provide a selfcontained underwater breathing device wherein the diaphragin which operates theair-demand valve is not exposed to the water surrounding the device andtherefore is not subjected to any inertia except that due to its ownmass and that of the air in the device.

Another object is to provide a self-contained underwater breathingdevice wherein the valve-operating diaphragm is fully enclosed andprotected and the danger of rupture of the diaphragm is minimized.

Another object is to provide a self-contained underwater breathingdevice having two diaphragms one of which encloses the otherdiaphragm-whereby upon rupture of either diaphragm the device isoperative and therefore is not subject to failure by reason of therupture of either one of the diaphragms.

Another object is to provide a self-contained underwater breathingdevice wherein the valve-operating di aphragm is instantly responsive topressure differences in the lungs of the user.

Another object is to provide a self-contained underwater breathingapparatus wherein the air pressures within the device are instantly andconstantly equalized.

Another object is to provide'a self-contained under- Water breathingapparatus whcrein'a large diameter, highly sensitive, valve-operatingdiaphragm is employed which insures instant and accurate equalization ofair pressures in the device.

Other objects and advantages of the invention will appear from thefollowing description taken in connection with the appended drawingswherein:

FIGURE l is a fragmentary front elevational view of the device showingparticularly the pressure regulator and portions of the air lines andair tank;

FIG. 2 is an enlarged fragmentary sectional view taken along line 2-2 ofFIG. 1;

FIG. 3 is a somewhat diagrammatic showing of the device with partsbroken away and in section to show the interior construction, the devicebeing. shown in the condition it assumes during the inhale cycle;

FIG. 4 is a view similar to FIG. 3 only showing the device in thecondition it assumes during the exhale cycle;

FIG. 5 is a view of a section taken along line 5'5v of FIG. 4;

FIG. 6 is a View of a section taken along line 6-6 of FIG. 2;

FIG. 7 is a view of a section taken along line 7--7 of FIG. 2;

FIG. 8 is a view of a section taken along line 8 8 of FIG. 2; and

FIG. 9 is a View of a section taken along line 9 9 of FIG. 2.

The device in accordance with my invention includes a tank or ilask 10for containing compressed air, a regulator 11 connected to the flask 10by a clamp 12 for regulating the Withdrawal of air from the flask 10, anair hose 13 connected to the regulator, and a mouthpiece 14 connected tothe air hose 13 for inhaling air from the ilask through one part of theair hose and for exhaling air from the lungs through another part of theair hose. The clamp 12, the regulator 11, the air hose 13 `and themouthpiece together constitute an assembly which may :be detached fromthe flask 10 as a unit in order to permit replacement of the flask,which assembly `I designate as 'a breathing unit.

The flask 10 may be of any suitable conventional construction and is ofsufficient strength to contain air at the customary pressure ofapproximately .2,000 pounds per'square inch. It is provided with theusual neck 1`5 having an outlet passage 16 therein leading from theinterior of the tank. The clamp 12 is suitably formed to clamp theregulator 11 to the neck 15, a clamp screw (no't shown), having asuitable handle, being provided for tightening the clamp to draw Vtheregulator intoV sealing engagement with the neck and to hold theregulator on the neck until the clamp is released. The tank is providedwith the usual manually operated shut-off valve (not shown) for closingthe tank to prevent loss of air when the device is not in use andespecially where the tank is disconnected from the regulator.

The regulator 11 includes a body 26 having a recess therein providing aprimary reduction chamber 21. A primary valve housing 22 is threadedinto a bore 23 in the body 20 leading to the primary reduction chamber21. The primary valve housing 22 has a passage extending therethroughwhich provides communication between the outlet passage 16 of the tankand the primary reduction chamber 21. The primary valve housing 22 isformed with a tlange 24 for the purpose of engaging the clamp 12 andretaining the pressure regulator on the neck 15, which ange ispreferably of hexagonal shape in order to facilitate screwing theprimary valve housing into the body 2t).

The passage in the primary valve housing 22 is formed l with a circularbore portion 30 and orifice 31 and a second circular borev portion 32,all of which are in alignment. Thus the bore portions 30 and 32 and theorifice 31 provide a continuous passage for air from the outlet passage16 to the primary reduction chamber 21.

Formed around the orifice 31 is a valve seat 35 of annular form andhaving a reduced outer face or edge portion providing an annular valveseat of relatively narrow width.

A primary valve 36 is slidably disposed in the bore 30 for movementbetween closed position abutting the valve seat 35 and an open positionspaced from the valve seat. The primary valve 36 includes a body 37 ofgenerally square cross-sectional shape as seen particularly in FIG. 9 ofthe drawings and therefore a plurality of passages 38 are providedbetween the valve body 37 and the bore to permit air to pass around thevalve member.

The valve member 37 is provided with a recess 40 in which is disposed avalve insert formed of flexible resilient sealing material. The materialfrom which the insert 41 is formed is one which retains its resiliencyand sealing properties over long periods of use and is not subject todeterioration. Preferably, I form the insert from a suitable plastic,and for this purpose I have found that a polytetratluoroethylene plasticmarketed by E. I. du Pont de Nemours and Co., of Wilmington, Delaware,under the trade name Teon has provided excellent results.

The recess 40 is disposed axially of the primary valve member 37 and theinsert 41 is symmetrically disposed in the recess. Disposed axiallywithin the recess and within the insert 40 is an anvil element 42 formedof metal which is secured in the material of the valve member 37 belowthe bottom of the recess 49 so as to be held irmly and securely therein.The corresponding faces of the valve member 37, the insert 41 and theanvil 42 are very carefully machined so that they all lie in the sameplane and particularly the end faces of the insert 41 and the anvil 42.Preferably I form the assembly constituting the valve 36 by disposingthe insert and anvil in the recess 41 and staking the end face of thevalve member 37 to crimp the edge around the insert, whereafter the endfaces of all three members are machined olf so that they are ilush.

The valve 36 is urged into closed position against the valve seat by aspring 45. seated in a recess 46 in the valve member 37 and bearing atits outer end against a retainer 47 rigidly secured in the valve housing22 over the end of the bore 30. The seat member 47 is formed with anopening therein to permit the passage of air therethrough, and a screen48 is secured across the bore 30 by the member 47 for preventing thepassage ofany solid particles into the bore 30.

The outer side of the primary reduction chamber 21 is closed by adiaphragm 50 extending across the face of the body 20 and clampedthereto by an intake housing 51 secured in place by a plurality ofscrews 52 extending through the end wall of the housing 51 and threadedinto the body 2). The diaphragm 50 is formed from a suitable, tiexible,resilient, waterproof material, such as rubber. Carried centrally of thediaphragm Si) is a pusher member 55 having a stem 56 extending throughan opening 57 in the diaphragm 50 and secured to the diaphragm by a nut58. The nut 58 bears against a bearing washer 59a which serves to clampthe central portion of the diaphragm 56 between itself and the head ofthe push member 55. The push member has a head 59 on the inner side ofthe diaphragm adapted to bear against the head 60 of a push rod 61having a stem 62 positioned to en gage the exposed end of the anvil 42for moving the primary valve 36 away from its seat.

The head 60 of the push rod 61 is formed of generally squarecross-section and whereby there is provided passages 63 around the head6() from the inner portion of the bore 32 to the primary reductionchamber 21.

The push member 55 is normally urged inwardly to cause the push rod 61to move the valve 36 olf its seat by a spring 65 bearing at one endagainst the push member 55 and at the other end against a springretainer 66 having a flange portion 67a: bearing against the inner faceof the intake housing and secured to the body 20 by the screws 52 and acup portion 67 for retaining and seating the spring 65.

The primary valve serves to permit the ow of air from the flask 10 tomaintain a predetermined air pres sure within the primary reductionchamber 21. Preferably the pressure of the air maintained within theprimary reduction chamber 21 is about 50 to l0() pounds per square inch.Whenever the pressure of the air within the primary reduction chamber 21falls below the desired value, the spring 65 urges the pressure member55 inwardly, which in turn urges the push rod inwardly and thereby movesthe primary valve 36 away from its seat to let air pass through theoutlet passage 16, the screen 48, the passages 38, the valve orifice 31,the bore 32 and the passages 63 and into the primary reduction chamber21. When the desired pressure within the chamber 21 is reestablished,the diaphragm 5t) is moved outwardly against the force of the spring 65to thereby permit the spring 45 to seat the valve 36 and cut off furthergow of air from the tank to the primary reduction charn- Leading fromthe prima-ry reduction chamber 21 is a passage 70 which communicateswith a bore 71 in which is threaded a demand valve seat member 72 whichextends through suitably positioned openings in the diaphragm 50, thebottom wall of the intake housing 51, and the spring retainer 66 and thefoot of a bracket 73 hereinafter described more in detail. The valveseat member 72 takes the place of one of the screws 52 and secures thebracket 73 in place. The valve seat member 72 is formed with a flange 74seated against the bracket 73, and has a tapered seat portion at itsouter end providing an annular seat of relatively small width. A bore 75extends through the valve seat member 72 and provides communicationbetween the bore 71 and the interior of the intake housing 51.

The valve bore 75 is normally closed by a demand valve formed ofresilient sealing material such as rubber or a synthetic material suchas Tetlon The valve 80 is carried by a lever 81 pivotally supported asat 82 from the bracket 73. Thus the valve 80 is adapted to be moved intoand out of position in closing the valve port or passage 75. The valveS0 is normally urged into closed position by a spring which is seated atone end against the nut 58 and at the other end against the demand valvelever 81, the latter being formed with a boss or button 91 struck upfrom the material of the lever and which enters the corresponding end ofthe spring to retain the spring in its appropriate position relativelyto the lever S1.

A second valve-operating lever 100 is pivoted as at 101 to a bracket 102secured by one of thev screws 52, which lever 180 is adapted to operatethe demand valve lever 81 to open the demand valve. The lever 100 has aboss or button 163 formed with its outer end adapted to be actuated by abreather diaphragm 105 hereinafter described. The valve actuating lever100 is so arranged that it engages intermediate its ends and preferablyabout half way between its ends a boss or button 106 formed on the outerend of the lever 81.

lt will be seen from the foregoing that when the lever 188 is depressedit bears against the button 106 and effects a depression of the lever81, which raises the de# mand valve tl'off its seat to permit air toiiow from the primary reduction chamber 21 to' the passage-70, the bore71 and the portv75 and into the interior of the 'intake housing 51.

rlhe intake housing 51 and the valve operating or breather diaphragm 105together delinev an intake chamber 118 which is connected to theinterior of the flask through the passages hereinbefore described. Therelative sizes of thepassages connecting the interior of the flask withthe interior of the inlet chamber 110, and particularly the passagesleading from the pressure reduction chamber 21 to the intake chamber110, are such that the air is maintained in the intake chamber 110 atsubstantially the pressure of the medium surrounding ythe pressureregulator.

The intake housing is of generally cupped form and has a bottom wall 111of circular form and a side wall 112 upstanding therefrom. Extendingoutwardly from the outer end of the side wall 112 is a ilange 113 havingan upturned rim 114. The breather diaphragm 105 is formed from asuitable exible resilient material which is water-tight and which is notsubject to deterioration over a long period of use, or loss of exibilityand resilience, and preferably I form such diaphragm from rubber,reinforced with a nylon core. The breather diaphragm 105 has a centralportion 115 which is rigid and nonflexible and which has secured theretoon both faces thereof circular reinforcing plates 116 of thin metalsecured to the diaphragm in a suitable manner as by rivets 117.Outwardly of the reinforced portion is a tiexible resilient portion 116of annular form and outwardly thereof is a securing rim portion 119 ofgreater thickness which is sealingly secu-red to the ange 113 of theintake housing 51 by screws 120 which extend through the flange 113 andare secured by nuts 121.

Disposed outwardly of and in clamping engagement with the rim portion119 is a circular exhaust ring 125 of generally channel shape incross-section and having a main wall or web 126 and flanges 127 and 128extending inwardly therefrom providing a generally U shapedcrosssection.

Secured against the outer face of the ilange 128 of the exhaust ring isan exhaust diaphragm 136 which is generally similar in form andstructure to the breather diaphragm 195 except as hereinafter explained.Out-v wardly of the exhaust diaphragm 136 is a cover 131 of generallydisc-shaped form and having a wall portion 32, an inclined wall portion133 extending therefrom in which is provided a plurality of openings134. Outwardly beyond the wall portion 133 is a flange 135 having adownturned rim 135a. The securing screws 120 extend through the liangeportions 135 and secure the cover 131 in place on the exhaust ring 125and at the same time clamp the rim portion 136 of the diaphragm 130between the flange 135 and the flange 128. The diaphragms 130 and 105deline therebetween an exhaust chamber 140 which communicates with theexterior of the pressure regulator through an exhaust valve now to bedescribed.

The diaphragm 130 has a central portion 141 which is reinforced byreinforcing members 142 'secured by,

which preferably are disposed in a circumferential series about thecenter of the diaphragm 13G.

The exhaust openings `.145 are normally closed by an exhaust valve 146which takes the for-m of a check valve which opens whenever the pressurein the exhaust chamber 148 is greater than the pressure on the exteriorof the diaphragm 138. To this end the valve 146 is formed of suitableresilient material such as rubber, and has a circular portion 147 whichnormally overlies all of the openings but which is yieldable and isdisplaced away from the openings 145 whenever the pressure within theexhaust chamber 140 exceeds the pressure on the exterior face of thediaphragm. The valve 146 also has a stem portion 148 which extendsthrough an opening in the'diaphragrn 138 and a head portion 149 whichserves to retain the stem portion 148 in the diaphragm 131).

A push rod 156 of generally U shaped form is secured to the inner faceof the diaphragm 13) by the head 149. The push rod is so dimensioned andpositioned that when the diaphragm 130 is moved inwardly a suiicientamount the push rod 150 bears against the central portion of thebreather diaphragm 105 and moves it inwardly for a purpose hereinafterdescribed.

Extending from the inlet chamber 110 is an outlet connection 160 andextending from the exhaust chamber 140 is a similar inlet connection161. The air hose 13 ir1- clude's an intake or inhale portion 162connected as by a clamp 163 to the outlet connection 169 and an exhaustor exhale .portion 164 connected as by a clamp 165 to the connector 161.The two hose portions 162 and 164 are formed of corrugated rubber hoseof conventional form.

The connecting portions 16) and 161 may be formed as separate membersand welded into suitable openings in the intake housing and exhaust ringrespectively, or they may vbe formed integrally therewith.

Connected between the ends of the hose portions 162 and 164 is themouthpiece l14 now to be described. The mouthpiece 14 includes a tubularportion 173 connected at its ends respectively to the corresponding endsof the hose portions 162 and 164 in a suitable manner, as by j hoseclamps and 176 respectively, and having a bore 174 providingcommunication between the interiors of the portions 162 and 164.Extending from the main body portion 173 of the mouthpiece 14 is alateral portion 177.V

having a bore 178 extending therethrough and'leadin'g from the bore 174to the exterior. The mouthpiece has the usual shield or apron 179 andtooth grip lugs 190.

The lateral portion 177 extends from the main body 173 in oiset relationthereto and above the medial plane passing through the axis thereof.Thus when the mouthpiece is in the normal position in the mouth of theuser, the center of the bore 174 is disposed below the center line ofthe bore or passage 17S. Consequently, any saliva which enters thepassage 178 from the mouth of the user, will pass downwardly into thelower portionr of the bore 174 and will be trapped therein and will nottend to return to the mouth of the user. The trapped saliva will beexpelled from the mouthpiece during the exhalation cycle.

Disposed in the ends of the body 173 are check valves 181i and 181. Thevalves 186 and 181 are identical in construction and are so arranged asto permit only a one-way flow of air through the hose. Thus the valve18) permits how of air from the hose portion 162 into the bore 174 butnot in reverse direction and the valve 181 permits the ilow of air fromthe bore 174 into the hose portion 164 but not in a reverse direction.Each valve includes a rigid cylindrical body portion 182 which isinserted in the end of the mouthpiece body 173 and secured therein bythe resiliency of the material of the body 173 and the clamping actionof the corresponding hose clamp. The portion 182 carries a partition 183formed with a plurality of ports 184 preferably of segmental shape. Theports are normally closed, but each valve member has a head 185 whichnormally overlies the ports 184 but which is sui'liciently liexible andyielding to be displaced away from the ports 184 upon air pressure beingapplied thereto through the ports. The valve is secured in the partitionby a stem 186 and a head 187.

The bodies of the valves 180 and 181 preferably are formed of a rigidmaterial such as a suitable rigid plastic, and the valve members 185preferably are formed of a flexible resilient material such as rubber orsynthetic rubber.

In the use of the device in accordance with my invention the pressureregulator, with the air hose and mouthpiece attached, is connected to atank by the clamp 12, the clamping screw (not shown) being tightened soas to firmly clamp the outer end of the valve housing 22 against theneck 15 of the ilask in sealing engagement therewith and to therebyplace the bore 30 in communication with the outlet passage 16 of theflask.

The shut-oil valve (not shown) is opened to admit air into the regulatorfrom the ask. inasmuch as initially the pressure in the chamber 21 is atthat of the medium surrounding the device, the spring 65 causes thepressure member 55 to urge the push rod 61 downwardly to -bear againstthe anvil 42 and maintain the valve 36 in open position. Thus the airfrom the ask may pass through the passage 16, the bore 30, the passages38, the port 31, the bore 32 and the passages 63 into the chamber 21.Assuming the device to be in air, the pressure in the intake chamber 110and the exhaust chamber 140 is equal and the diaphragm 105 is notdisplaced from its normal position. Accordingly, the demand valve 80 isin closed position and air cannot escape therethrough.

Thus the pressure in the chamber 21 builds up to the desired amount,namely around 50 to 100 pounds per square inch. When this occurs thediaphragm 50 is forced outwardly against the force of the spring 65 asuicient amount to permit the valve 36 to close and cut olf any furtherflow of air from the flask 10.

The user inserts the grip lugs 190 in his mouth and between his teethwith the shield 179 between his lips and his teeth so that there is noleakage of air past the mouthpiece. The exhaust diaphragm 130 issubjected to the pressure of the surrounding medium, whether it be airor water. Assuming now that the user has entered the water and the bodyof the user and the pressure regulator are submerged in the water at apredetermined depth, the water exerts a pressure on the exhaustdiaphragm 130 determined by the depth at which the pressure regulatorandmore particularly the diaphragm 13G-is located.

Assuming that the user is neither exhaling nor inhaling, the apparatusis in what I term the static condition wherein the demand valve 80, thecheck valves 180 and 181, and the exhaust valve 146 are closed and thediaphragms 105 and 130 are in their normal neutral positions. Thepressures throughout the device then are equalized. The water pressureexerted on the outer face of the diaphragm 130 tends to displace thediaphragm 130 inwardly a very slight amount and, owing to the resiliencyof the diaphragm, it is stressed in a direction setting up a counter orrestoring force on the diaphragm, tending to restore it to its originalposition. On the inner face of the diaphragm there is an air pressureforce equal to the water pressure force on the outer face of thediaphragm less the counterforce tending to restore the diaphragm to itsinitial position. In other words, the force exerted by the air pressureon the inner face of the diaphragm 130 is less than the force exerted bythe water pressure by the amount corresponding to the energy stored inthe diaphragm by reason of its displacement and tending to restore it toits normal position and condition.

Since the pressure in the exhaust chamber is slightly less than that ofthe surrounding medium, and since the user is neither inhaling norexhaling, the exhale valve 181 may open slightly and similarly theinhale valve 180 may open slightly to equalize the pressure within theintake chamber 110 and the exhaust chamber 140. When the pressure isthus equalized the breather diaphragm 105 is in its neutral position andthe demand valve remains closed. Thus the pressure throughout the systemis equalized at a value equal to the pressure in the exhaust chamber,which is slightly less than that of the surrounding water.

When -the user inhales, the inhale valve 180 (as shown in FIG. 3) isopened to allow air to pass therethrough to the mouthpiece and into thelungs of the user. This action reduces the pressure within the intakechamber 110, whereupon the breather diaphragm 105 is drawn inwardly andbears against the button 103 to rock the lever which in turn rocks thelever 81 and fully opens the demand valve 80. The inward movement of thediaphragm causes a reduction in pressure in the exhaust chamber, and theexhaust diaphragm moves inwardly accordingly. The reduction of pressurein the intake chamber and consequent inward movement of the diaphragmresulting from the inhalation causes the valve 180 to be opened so thatthe air can flow through to the lungs of the user. The valve 181 remainsclosed. Air flows from the pressure regulator chamber 21 into the intakechamber 110 in a quantity sufficient to meet the demand of theinhalation by the user.

Upon the cessation of the inhalation by the user the check valve 180closes and pressure is built up in the chamber 110 until the diaphragm105 is returned to its initial position (as shown in FIG. 2) and allowsthe demand valve 80 to close, whereupon no more air ilows from theprimary chamber 21 into the intake chamber 110. The diaphragm 105 alsoreturns to its original position.

When the user exhales the exhale valve 181 is opened (as shown in FIG.4) and air passes therethrough and through the hose portion 164 into theexhaust chamber 140. The increase in pressure in the exhaust chambermoves the diaphragm 130 outwardly and finally causes the exhaust valve146 to open and allow air to be discharged to the exterior of theregulator and into the surrounding water through the opening 145. Salivatrapped in the lower portion of the bore 174 will be expelled throughthe valve 181 by the exhalation of the user. The inhale valve ismaintained closed during the exhale portion of the cycle.

During the exhale portion of the cycle the exhaust diaphragm 130 ismoved outwardly as above described, and the exhaust valve 146 is opened.At the same time, owing to the pressure established in the exhaustchamber 140, the breather diaphragm 105 is moved inwardly a slight amoutto open the demand valve slightly and equalize all pressure in theinhale hose portion 162 with that in the remainder of the device. Thisequalizing of pressure assists in exhaling because the user does nothave to exhale against the entire pressure of the exhaust valve, but hisexhalation is assisted by the pressure of the air passing through thehose from the intake chamber.

During normal use of the device the push rod 150, carried by the exhaustdiaphragm 130, remains spaced from and out of engagement with thebreather diaphragm 105. However, should the device be submergedsubstantially-that is to say, for example, a distance of several feetunder the surface of the water without any inhalation by the user-thepressure of the water will cause the exhaust diaphragm 130 to be movedinwardly to an extent to which the push rod effects inward movement ofthe end of the lever 100 and thereby opens the demand valve S0 to allowair to pass into the intake chamber and through the inhale valve andinto the lungs of the user. Thus even should the user forget to inhale,air will be supplied to his lungs and will cause involuntary ac- 9 tionwhich will result in the user exhaling and initiating the breathingcycle.

It will be noted that the breather diaphragm 1105 is not exposed tocontact with the surrounding water but is exposed to air on both sides.The outer face of the breather diaphragm 105 is subjected to thepressure of the air in the exhaust chamber which is at the exhaustpressure or a lesser pressure, depending upon the portions of cycle atany moment. The inner face of the breather diaphragm 105 is subjected toa maximum pressure equal to the pressure of the air passing from theorifice 75 of the demand valve.

The breather diaphragm, which is the diaphragm against which the usermust exert the pressure of his lungs in order to actuate the diaphragmis exposed only to air on each facev thereof. It is not exposed to waterpressure. Accordingly the breather diaphragm may move relatively freelyduring both the exhale and inhale cycle as the only inertia is that ofthe diaphragm itself and of the air. On the other hand, in aconventional underwater breathing device the water pressure is alwaysapplied against the `outer face of the breather diaphragm andconsequently upon inward movement of the diaphragm the water inertia-tends -to continue the inward movement of the diaphragm. On the otherhand, upon the initiation of the outward movement of the diaphragm theinitial inertia of the water must be overcome. In the present devicethere is no water inertia to be overcome or to effect continued inwardmovement of the diaphragm.

The elimination of the aforesaid water inertia on the breather diaphragmresults in a more uniform breathing action and less resistance =to thenormal breathing action. Thus the device of the present invention ismore comfortable and satisfactory to use inasmuch as the user does nothave to exert any abnormal inhale and exhale force to operate the deviceas in the case of prior devices.

It will be noted that the breather diaphragm in the device of thepresent invention is not subjected to the pressure of the water.Accordingly there is no tendency for the diaphragm to be tilted orcocked when the device is in such position that one outer or peripheralportion of the diaphragm is at a lower depth than another peripheralportion. Accordingly, the demand valve is opened only when such actionis dictated by the desired pressure in the intake chamber resulting fromthe inhale cycle and there is no possibility of the demand valve beingopened or held against opening owing to any diierential in waterpressure `over the different portions of the face of the breatherdiaphragm.

The exhaust diaphragm 130 also is provided with a rigid central portionand this diaphragm moreover does not normally act to operate the demandvalve. However, should the device be in such position that there is agreater pressure on one peripheral portion thereof than on another owingto the position of the diaphragm and to the fact that the water pressureon one peripheral portion is greater than on another, neverthelessbecause of the fact that the push rod 150 is located centrally of theexhaust diaphragm and acts on the exact central portion of the breatherdiaphragm there will be no actuation of the demand valve because of anysuch differential pressure exerted by the water on the exhaust diaphragm130.

It will be seen that inasmuch as the breather diaphragm M is notsubjected to the pressure of the water surrounding the regulator, thereis no danger of any spontaneous loss of air by reason of the fact that agreater pressure is exerted on the breather diaphragm than is exerted onthe exhaust valve. Accordingly, it is immaterial whether the exhaustvalve be placed above or below or any particular distance above thebreather diaphragm. While I have shown a device wherein the exhaustvalve is placed relatively close to the breather diaphragm, this is notat all necessary and the exhaust valve may be placed at any locationabove or below the breather diaphragm. Accordingly, it is immaterialwhat 10 position the device takes relatively to the water in which it islocated. Thus the user may swim in the normal face down position, or onhis back, or in any other position without causing spontaneous loss ofair through the exhaust valve.

The device of the present invention requires a miniexhaust valve andequalizes all pressures from the inlet chamber to the exhaust valve.

inasmuch as the breather diaphragm of the present invention is notsubject to cooking or water inertia and since it is eiective only at thecenter thereof to open the demand valve, the diaphragm may be madecomparatively larger than diaphragms employed in prior art devices andtherefore is muchmore sensitive than smaller diaphragms.

The provision of two diaphragms provides a double protection for vthedevice. For example, should the breather diaphragm be ruptured or leak,the outer, exhaust diaphragm would then functionl both as a breatherdiaphragm and as an exhaust valve diaphragm and the device would operateeven though the breather diaphragm were not effective. Thus, even thoughthe inner diaphragm were ruptured or otherwise become ineffective, theuser would still be able to operate the demand valve by the normalbreathing operation and would be supplied with air to permit his returnto the surface. Also, if the outer, exhaust diaphragm should be rupturedor otherwise caused to leak, the device would still operate. Under suchcircumstances, the breather diaphragm would continue to operate butwould be subjected to the pressure of the water thereon. In this eventthe exhale valve 181 would function as the exhaust valve, and thebreather diaphragm 10S would be subjected to the pressure of the wateron the outer face thereof as in the case of conventional prior artunderwater breathing devices.

It will be seen from the foregoing that the device of my invention isrelatively simple, and no parts thereof require any criticaladjustments. The simplicity thereof will assure long life without costlyrepairs and it can be manufactured and assembled readily. Moreover, itis extremely safe and positive in action, and provides not only all ofthe features and advantages of prior devices but embodies a number offeatures not present or possible in devices constructed in accordancewith prior art teachings. It provides extremely easy breathing andfurnishes air instantly to the user in any quantity desired.

The mouthpiece is of such construction that the valve chamber serves asa saliva trap from which the saliva is expelled by the exhaled airduring the exhalation portion `of the breathing cycle. Moreover, thevalve chamber is depressed, and thus does not interfere with the facemask customarily worn by the user of the breathing device.

While I have referred to the device herein as being employed to supplyair to the user, it will be understood that the device is not restrictedto such use but may be employed to supply any breathable gas to theuser. For example, under certain circumstances it may be desirable toprovide in the tank or ask a breathable gas consisting of air enrichedwith oxygen, or pure oxygen. It will be understood that the mechanism ofthe device does not depend upon the nature of the gas supplied by theflask, but it is suitable for operation with any breathable gas.

I claim:

l. Breathing apparatus comprising a casing, a firstrespiration-responsive diaphragm defining with said casing an intakechamber adapted to be connected to a source of breathable gas underpressure, a normally routlet passage connecting said dreduction intakechamber, a normally closed demand valve actuated closed intake valvecontrolled by said first diaphragm for controlling the supply of gas tosaid intake chamber, a second respiration-responsive diaphragm definingwith said casing and said first diaphragm an exhaust chamber and exposedon its outer face to the surrounding fiuid medium, a normally closedexhaust valve in said second diaphragm, a conduit connected between saidchambers and having an opening intermediate its ends for connecting saidconduit to a point` of use, and check valves in said conduit on oppositesides of said opening.

2. Breathing apparatus comprising a. casing, a firstrespiration-responsive diaphragm defining with said casing an intakechamber adapted to be connected to a source of breathable gas underpressure, a normally closed intake valve controlled by said firstdiaphragm for controlling the supply of gas to said intake chamber, asecond respiration-responsive diaphragm defining with said casing andsaid iirst diaphragm an exhaust chamber and exposed on its outer face tothe surrounding fluid medium, a normally closed exhaust valve in saidsecond diaphragm, means extending inwardly from said second diaphragmpositioned to engage said first diaphragm to cause it to open saidintake valve when the pressure of the surrounding fiuid medium exceedsthe pressure in said second chamber by a predetermined amount, a conduitconnected between said chambers and having an opening intermediate itsends for connecting said conduit to a point of use, and check valves insaid conduit on opposite sides of said opening.

3. Breathing apparatus comprising a casing defining a pressure reductionchamber having an inlet adapted to be connected to a source ofbreathable gas under pressure, a valve controlled by the pressure insaid reduction chamber for controlling the admission of gas into saidreduction chamber, a first respiration-responsive diaphragm deiiningwith said casing an intake chamber, means defining an outlet passageconnecting said reduction chamber and Said intake chamber, a normallyclosed demand valve actuated by said first diaphragm for controlling thefiow of gas from said reduction chamber to said intake chamber, a secondrespiration responsive diaphragm defining with said casing and saidfirst diaphragm and exposed on its outer face to the surrounding fluidmedium, an exhaust chamber, a normally closed, exhaust valve in saidsecond diaphragm, a conduit connected between said intake chamber andsaid exhaust chamber and having an opening intermediate its ends forconnecting said conduit to a point of use, and intake and exhaust checkvalves in said conduit on opposite sides of said opening respectively.

4. Breathing apparatus comprising a casing, a firstrespiration-responsive diaphragm defining with said casing an intakechamber adapted to be connected to a source of breathable gas underpressure, a normally closed intake valve controlled by said firstdiaphragm for controlling the supply of gas to said intake chamber, asecond respiration-responsive diaphragm defining with said casing aninclosure for said first diaphragm and defining with said firstdiaphragm and said casing an exhaust chamber said second diaphragm beingexposed on its outer face to the surrounding iiuid medium, an exhaustopening leading from said exhaust chamber, a normally closed exhaustvalve controlling said exhaust opening, a conduit connected between saidchambers and having an opening intermediate its ends for connecting saidconduit to a point of use, and check valves in said conduit on oppositesides of said opening.

'valve controlled by the pressure in said reduction chamber forcontrolling the admission of gas into said reduction fchamber, a firstrespiration-responsive diaphragm defining with said casing an intakechamber, means defining an chamber and said by said first diaphragm forcontrolling the fiow of gas from said reduction chamber to said intakechamber, a second respiration-responsive diaphragm defining with saidcasing an inclosure for said first diaphragm and defining with said rstdiaphragm and said casing an exhaust chamber said second diaphragm beingexposed on its outer face to the surrounding uid medium, a normallyclosed exhaust valve in said second diaphragm, a conduit connectedbctween said intake chamber and said exhaust chamber and having anopening intermediate its ends for connecting said conduit to a point ofuse, and intake and exhaust check valves in said conduit on oppositesides of said opening respectively.

6. Breathing apparatus comprising a casing of generally cup shape, afirst respiration-responsive diaphragm extending across the open end ofsaid casing and secured to the casing to define therewith a spaceinclosed from the surrounding :fluid medium, said first diaphragm beingexposed in its outer face to the surrounding fiuid medium, a secondrespiration-responsive diaphragm disposed in said inclosed space andextending across and secured to said casing to define with said casingan intake chamber adapted to be connected to a source of breathable gasunder pressure, said second diaphragm being in spaced, face-to-facerelation with said first diaphragm and defining with said casing andsaid first diaphragm an exhaust chamber, a normally closed intake valvein said intake chamber, means actuated by said first diaphragm foractuating said intake valve, an exhaust opening leading from saidexhaust chamber, a normally closed exhaust valve controlling saidexhaust opening, a conduit connected between said chambers and having anopening intermediate its ends for connecting said conduit to a point ofuse, and check valves in said conduit on opposite sides of said opening.

7. Breathing apparatus comprising a casing, a firstrespiration-responsive diaphragm extending across and secured to saidcasing to define with said casing an intake chamber adapted to beconnected to a source of breathable gas under pressure, a secondrespiration-responsive diaphragm extending across said casing andsecured to the casing to define therewith a space inclosing said firstdiaphragm from the surrounding fluid medium, said diaphragm beingexposed in its outer face to the surrounding uid medium, said seconddiaphragm being in spaced faceto-face relation with said first diaphragmand defining with Said casing and said first diaphragm an exhaustchamber, a normally closed intake valve in said intake chamber, meansactuated by said first diaphragm for actuating said intake valve, anexhaust opening leading from said exhaust chamber, a normally closedexhaust valve controlling said exhaust opening, a conduit connectedbetween said chambers and having an opening intermediate its ends forconnecting said conduit to a point of use, with check valves in saidconduit on opposite sides of said opening.

8. Breathing apparatus according to claim 7 wherein said seconddiaphragm carries a projection positioned to engage said iirst diaphragmto cause the latter to open said intake valve when the pressure of thesurrounding medium exceeds the pressure in said exhaust chamber by apredetermined amount.

9. Breathing apparatus comprising a casing, a firstrespiration-responsive diaphragm disposed in and secured to the casingto define therewith a space enclosed from the surrounding uid medium,said first diaphragm being exposed in its outer face to the surroundingfiuid medium, a second respiration-responsive diaphragm disposed in saidspace and extending across and secured to said casing to define withsaid casing an intake chamber adapted to be connected to a source ofbreathable gas under pressure, said second diaphragm being in spacedface-to-face relation with said first diaphragm and dening with saidcasing and said first diaphragm an exhaust chamber, a normally closedintake valve in said intake chamber, means actuated by said firstdiaphragm for actuating said intake valve, an exhaust opening leadingfrom said exhaust chamber, a normally closed exhaust valve carried bysaid second diaphragm controlling said exhaust opening, a projection onsaid valve positioned to engage said first diaphragm to cause it to opensaid intake valve when the pressure of the surrounding uid mediumexceeds the pressure in said exhaust chamber by ya predetermined amount,a conduit connected between said chambers and having an openingintermediate its ends for connecting said conduit to a point of use,with check valves in said conduit on Opposite sides of said opening.

References Cited in the le of this patent UNITED STATES PATENTS RyanJan. 13, McCaa Apr. 19, Seeler May 13, Holmes Sept. 2, De Sanctis I an.31, Fay Aug. 7, Page Feb. 18, Adams Jan. 12,

FOREIGN PATENTS Great Britain July 2, France Sept. 13,

